Optics Young's Double Slit Experiment and Generalizations to N-slits

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This applet demonstrates diffraction of monochromatic waves. through N-slits.

Variables you can adjust:

d - the distance between the slits

l - the wavelength of the incident light

a - the width of the slits

N - the number of slits

Collected formulae on this phenomena is available in dvi, postscript, pdf or. html formats.

Things to do

Single Slit Effects

Note the irradiance minima when sin(alpha) = 0, where alpha = (ka/2) sin(theta).

Note the irradiance maxima where alpha = +/- 1.43pi, +/- 2.459pi, ...

Double Slit Effects

Note the irradiance minima when cos(delta) = 0, where delta = (kd/2) sin(theta).

Note the half-fringes or missing orders that occur when d/a = n, where n is an integer.

N Slit Effects

Note the irradiance minima when sin(N*delta) = 0, where delta = (kd/2) sin(theta).

Notice the N-2 subsidiary minima between the principle maxima.

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Comments to ganderson@northwestern.edu